1. Field of the Invention
The present invention relates generally to cotton harvesters, and more specifically to an improved cotton picker row unit structure and cotton harvester utilizing the improved row unit structure for harvesting cotton planted in narrowly spaced rows.
2) Related Art
In the past, cotton harvesters of the spindle type such as the John Deere model 9910 Cotton Picker included row units with front and rear picker drums located to pick cotton from the opposite sides of the row. The forward drum typically included sixteen upright bars of spindles and the rear drum had twelve bars of spindles. This configuration of drums required a relatively wide housing which limited the harvester to harvesting only two widely spaced (38 or 40 inches; 96 to 102 centimeter) rows.
Recently, narrow row cotton harvesters which are capable of harvesting four or more rows of cotton spaced as narrowly as 76 centimeters (30 inches) have been commercially available. One type of narrow row harvester, exemplified by the Case-IH model 2055 Cotton Picker, has nested units with two 12-bar drums on opposite sides of the row. A second type of narrow row harvester, exemplified by the John Deere model 9960 Cotton Picker, utilizes two 12-bar drums located one behind the other on the same side of the row. Both the Case-IH machine and the Deere machine can harvest cotton planted in a variety of row spacings from 76 to 102 centimeters (30 to 40 inches), including a number of skip row patterns.
Despite the flexibility of the machines available today, there are still a number of row spacings that picking units can not harvest. This inability to harvest some row spacings is especially true in developing countries where there is a growing interest in the mechanical harvesting of cotton but where very narrow row spacings of 60 centimeters (23.6 inches) or 30 centimeters (11.3 inches) are common. For example, in China the cotton often is planted in a 30-60 centimeter skip row pattern. The row units on present cotton harvesters, including the in-line Deere unit with two twelve-bar drums available on the Deere 9960 Cotton Picker, have widths too large to harvest such narrowly spaced rows without damage to an adjacent row of cotton plants. Lack of sufficiently narrow picking unit has limited the amount of very narrow row cotton that can be harvested mechanically.
Relatively high costs of mechanical cotton picking equipment is another problem associated with cotton harvesters. This problem is especially prevalent in developing countries where financial resources are extremely limited and a self-propelled machine dedicated only to cotton harvesting is not practical.
In-line units such as utilized on the Deere 9960 Cotton Picker include side suction door structure which receives cotton doffed rearwardly and outwardly from the spindles on the front and rear drums. The door structure diverges outwardly in the rearward direction from the forward drum area. The door structure has a cross section that continues to expand outwardly behind the rear post adjacent the rear drum. The expanded cross section facilitates entry of cotton from the rear drum into the stream of picked cotton that is moving towards the door opening to the cotton conveying ducts. However, such a configuration results in a row unit having a profile which is too wide to accommodate harvesting of very narrow row cotton. In addition, the rear doffer on the row unit commonly must handle more stalks and trash than the forward doffer, and the indirect path to the rear suction door can be prone to blockages which reduce productivity.